1. Field of the Invention
The present invention relates to an organism information measuring device capable of measuring an organism information such as pulse rate under a state of being mounted to a wrist (arm), and an organism information measuring method.
2. Description of the Prior Art
Due to an increase in concern for health care in recent years, various kinds of organism information measuring devices, which can measure various organism information such as pulse rate while being mounted to the wrist (arm) and the like intact, have been proposed. See, for example, Japanese Published Patent Application No. 2001-078973 (Patent Document 1).
In the organism information measuring device described in Patent Document 1, under the state of being mounted to the wrist, a light is irradiated from an LED toward an organism. Backward scattered light from blood in a blood vessel is received by a photodiode, and the pulse rate is calculated by extracting a pulse signal from the backward scattered light. Especially, since a measurement of the pulse rate can be easily performed while being mounted to the wrist intact, it is simply used by a user.
By the way, in the organism information terminal device described in the above Patent Document 1, there has been a fear that, in addition to the fact that the light containing a pulse information is received when receiving the backward scattered light from the organism by the photodiode, there is received a light containing no pulse information, for example, a light directly entering from the LED, a light reflected by an organism surface, or a light reflected by a transparent glass disposed above the LED. By this, in the photodiode, a noise (electrical disturbance) increases, and a reduction in S/N ratio has occurred. Accordingly, there has been a possibility that an accurate organism information cannot be measured.